Effect of weight loss on tongue fat

(A) Change in tongue fat volume with weight loss. Three dimensional reconstruction of tongue (red) and tongue fat (yellow) derived from axial MRI (T1-weighted, spin echo, 3 mm slice thickness) and Dixon fat-only MRI (3 mm slice thickness), demonstrating loss of tongue fat between baseline and a six-month follow-up visit. The tongue is defined as the genioglossus muscle, and tongue fat is defined as all fat within the genioglossus.
(B,C) The relationship of percentage change in tongue fat volume with percentage change in weight and AHI. The associations between the percentage change in tongue fat and weight loss (B) and AHI change (C) are illustrated among obese patients with obstructive sleep apnea undergoing surgical or medical weight loss. Strong positive correlations were observed between tongue fat change and both measures (Pearson's partial rhos = 0.62, p<0.0001), in covariate adjusted analyses. Mediation analyses suggest that percentage change in tongue fat was the primary upper airway mediator between percentage weight loss and percentage reductions in AHI.